A recent international study suggests that three existing medications could offer unexpected new hope in the fight against Alzheimer’s disease. Led by researchers at the University of Exeter, the study analyzed more than 80 commonly used drugs to identify those most likely to prevent or slow the neurodegenerative disease.
The top candidates include the shingles vaccine (Zostavax), sildenafil—better known as Viagra—and riluzole, a medication used to treat motor neuron disease. Among these, the shingles vaccine emerged as the most promising due to its safety profile and evidence linking it to a reduced risk of Alzheimer’s. Studies indicate that individuals who received the vaccine were 16% less likely to develop the disease.
Repurposing existing drugs offers a major advantage over developing new medications, which can take 10–15 years and cost billions of dollars without guaranteed success. Drugs already proven safe in humans allow for a faster, lower-risk route to potentially life-changing treatments.
The study involved 21 dementia specialists from universities, hospitals, and pharmaceutical companies, along with input from Alzheimer’s patients. Each of the top three drugs was selected for its ability to target biological processes associated with Alzheimer’s and for promising results in laboratory and animal studies.
- Shingles vaccine (Zostavax): May modify immune system responses linked to Alzheimer’s, offering protective effects against harmful changes in the brain.
- Sildenafil (Viagra): Experiments in mice suggest it may protect neurons and reduce tau protein deposits in the brain while improving memory and cognition, possibly by increasing blood flow.
- Riluzole: Animal studies indicate it can improve cognitive function and lower tau protein levels in the brain.
Researchers are calling for clinical trials to determine whether these drugs can help patients already showing Alzheimer’s symptoms or those at high risk of developing the disease.
In addition to the top three, five other drugs showed some potential but were deemed less promising: fingolimod (used for multiple sclerosis), vortioxetine (for major depressive disorder), micro-lithium (for depression), dasatinib (for leukemia), and cytisine (a natural aid for smoking cessation).
Dr. Ann Corbett, a professor of dementia research at the University of Exeter, emphasized the importance of exploring all research avenues: “Repurposing drugs is a vital part of turning today’s medicine into tomorrow’s treatments. These promising candidates now need further investigation through clinical trials to understand their true potential against Alzheimer’s.”
As Alzheimer’s continues to affect tens of millions worldwide—a figure projected to surpass 150 million by 2050—these findings offer hope for faster, safer interventions using medications already familiar to patients and clinicians alike.
